In motor-driven vehicles, a parking brake is generally provided for arresting or fixing the motor vehicle at a standstill and especially in connection with the parking of the motor vehicle. When again beginning to drive the motor vehicle, the releasing of the set parking brake can be forgotten by the operator of the motor vehicle; the driving with a set or applied parking brake can, however, lead to an impairment or damage of the braking system of the motor vehicle. As a result, driving with a set or applied parking brake should be avoided.
From the German Patent Publication DE 198 14 657 A1 with a control and/or regulating arrangement for an electrical parking brake arrangement of motor vehicles, forming the general background of this art, it is known to provide a sensor unit for measuring the wheel rotational speed of the vehicle, by means of which the two driving conditions, standstill or parking and driving, of the vehicle can be recognized. With this information by itself, a driving of the motor vehicle is often erroneously assumed, even in connection with an undesired and unintended rolling of the vehicle (for example due to diminishing or slackening braking force or insufficient setting or applying of the parking brake), whereby critical situations impairing the safety can arise.